Endoscopic retrograde cholangiopancreatography (ERCP) is a technique used for viewing and treating the ducts that drain the liver and pancreas. Biliary ducts form a drainage routes into the duodenum from the liver and gallbladder and they join the pancreatic duct, just before they drain into the duodenum about 3 inches from the stomach. The drainage opening is called the papilla (Ampulla of Vater). The papilla is surrounded by a circular muscle, called the sphincter of Oddi. During ERCP, X-ray contrast dye is injected into the bile duct, the pancreatic duct, or both via a catheter disposed through a working channel of an endoscope.
Two commonly used types of catheters used during ERCP procedures (particularly where a catheter may be exchanged) are referred to as “long-wire” catheters and “short-wire” catheters. A long-wire catheter is one in which a wire guide lumen is provided through the major length of the catheter. That is, in a catheter configured for use with long-wire procedures, the wire guide lumen extends through more than half, most, or all of the catheter's length. In catheters for short-wire procedures, the wire guide lumen may not extend the entire length of the catheter. In this type of catheter, the wire guide lumen may extend only from the distal end of the terminal-end device to a point intermediate the distal and proximal ends of the catheter, and often the wire guide extends through less than half or only a very small percentage of the catheter's length (defined herein as a minor length). This shorter lumen is the only portion of the catheter encompassing the wire guide during a short wire operation.
The decreased friction and the lack of a need for a wire guide that is at least about twice as long as the catheter are generally considered advantages of a short-wire catheter, although the pushability of a catheter without a wire guide engaged into a long-wire lumen may be less than that of a long-wire catheter so engaged. Short-wire catheters are often easier to exchange than catheters having the wire guide lumen extending the entire length of the catheter. This is because the wire guide need not be as long as a “long wire” configuration, which requires that a length of the wire guide extending outside the patient's body be longer than the portion of the catheter extending over the long wire guide in order for a doctor or assistant to maintain a grasp on the wire guide (to avoid undesired movement or displacement thereof). The short wire guide configuration catheters (known also as “rapid exchange catheters) also create less friction during mounting and exchange operations due to the shorter wire guide lumen, leading to a reduced likelihood of displacing the wire guide after it has been positioned, often under radiography, to a desired position/orientation.
Stents may be placed into the bile and/or pancreatic ducts to bypass strictures of the duct. These narrowed areas of the bile or pancreatic duct may be caused by—for example—inflammation, scar tissue, or tumors that cause blockage of normal duct drainage. Metal and/or plastic stents may be used, depending upon the medical indications. In some circumstances, it may be useful to provide a plurality of stents that cross a single stricture in generally parallel fashion, such as is shown—for example—in FIG. 1. The example of FIG. 1 shows two plastic biliary stents 197, 199 disposed through a biliary duct 182 and protruding through the Ampulla of Vater 184 (not to scale) into the duodenum. Such stents typically are placed by being directed to a target site over and along a guide catheter disposed through the stent lumen.
Placement of multiple biliary stents in bile duct stricture can be technically challenging, because difficulties may arise from accessing the stricture with repeated cannulation and guide wire placement. The subsequent exchanges done over a very long guide wire may increase the procedural complexity. In the conventional manner of delivering multiple stents to traverse a single stricture, repeated bile duct cannulation and exchanges are necessary in order to place multiple stents to attain the maximum lumen diameter for the stricture. Direct cannulation with the stent preloaded on stent-delivery catheter without a prior inserted wire guide may be difficult. Although it is possible to use a single wire guide left in place to direct a first (optionally pre-loaded) stent-delivery catheter to a target site, withdraw the stent-delivery catheter, recannulate the stricture, then re-introduce the same (reloaded) or a different (preloaded) stent-delivery catheter for placement of a second stent (repeated for any subsequent stent-placement), it would be advantageous to provide a system and method for serially placing a plurality of stents that would not necessitate the time, effort, and complexity of withdrawing and reintroducing a stent-delivery catheter for second and subsequent stents targeted to traverse a single stricture or to otherwise be delivered along a single wire guide.